Method of formatting signal in mobile communication system

ABSTRACT

A method for formatting a signal in a mobile communication system by appending a plurality of medium access control headers to a plurality of medium access control-service data units for data transfer between a mobile station and network in the mobile communication system. If the service data units have the same characteristics, a medium access control-protocol data unit is formed by successively coupling the service data units to any one of the medium access control headers. If the service data units have different characteristics, the protocol data unit is formed by sequentially coupling each of the service data units and each of the medium access control headers. The formed protocol data unit is then transformed into a transport block with a predetermined size. A medium access control sublayer formats medium access control-protocol data units according to transport channel characteristics in peer-to-peer communication in such a manner that the protocol data units can have different formats with respect to different transport channels. This makes it possible to provide more efficient functions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to a mobile communicationsystem, and more particularly to a method for formatting a signal in amobile communication system.

2. Description of the Prior Art

A conventional method for formatting a signal in a mobile communicationsystem will hereinafter be described with reference to FIGS. 1 a and 1b.

FIG. 1 a is a view illustrating a data flow for a non-automatic repeatrequest (ARQ)-type radio access bearer service to which the conventionalsignal formatting method is applied, and FIG. 1 b is a view illustratinga data flow for an ARQ-type radio access bearer service to which theconventional signal formatting method is applied.

A medium access control (MAC) sublayer or a mobile station utilizes aMAC-protocol data unit (PDU) for peer-to-peer communication with a peerMAC sublayer of a network.

The MAC-PDU contains fields necessary to the execution of a MACfunction.

In radio link control-user/control plane (RLC-U/C) layers, datatransferred from upper layers is segmented into payload units (PUs) andthen reassembled.

The PU is defined as a unit for the resending of an ARQ-type service,and it is dimensioned to -be suitable to the lowest data rate inconnection.

The RLC-U/C layers append headers for segmentation information andacknowledgment information respectively to the PUs and transfer theresultant RLC-U/C PDUs to the MAC sublayer.

The MAC sublayer, in turn, appends information multiplexing headersrespectively to the RLC-U/C PDUs from the RLC-U/C layers and producesthe resultant MAC-PDUs.

The MAC-PDU has a size corresponding to that of a transport block to alayer 1.

On the other hand, a non-ARQ-type variable rate service, the MAC-PDU ismapped into a transport block to be transferred to the layer 1, the sizeof which is variable.

As a result, in the non-ARQ-type variable rate service, the MAC-PDU isvariable in size. As shown in FIG. 1 a, the MAC-PDU includes a pluralityof MAC-service data units(SDUs).

In an ARQ-type fixed rate service, the MAC-PDU is determined in sizeaccording to the size of a transport block where the PU is fixed insize. As a result, the MAC-PDU includes only one MAC-SDU, as shown inFIG. 1 b.

As shown in FIG. 1 a, a physical layer transforms one multiplexingheader and one MAC-SDU or one multiplexing header and a plurality ofMAC-SDUs from the MAC sublayer into a transport block with apredetermined size. Also, as shown in FIG. 1 b, the physical layertransforms one multiplexing header and one MAC-SDU from the MAC sublayerinto a transport block with a predetermined size. Then, the physicallayer sends the, resultant transport block to the network through aphysical channel.

Upon receiving the transport block sent from the mobile station throughthe physical channel, the network performs the opposite procedure tothat of the mobile station to separate the received transport block intoone MAC header and one or more MAC-SDUs and perform the associatedsignal processing.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made for the effectiveimplementation of a medium access control sublayer function, and it isan object of the present invention to provide a method for formatting asignal in a mobile communication system, in which a medium accesscontrol sublayer formats medium access control-protocol data unitsaccording to transport channel characteristics in peer-to-peercommunication in such a manner that the protocol data units can havedifferent formats with respect to different transport channels.

In accordance with one aspect of the present invention, the above andother objects can be accomplished by a provision of a method forformatting a signal in a mobile communication system by appending aplurality of medium access control headers to a plurality of mediumaccess control-service data units for data transfer between a mobilestation and network in the mobile communication system, comprising thefirst step of, if the service data units have the same characteristics,forming a medium access control-protocol data unit by successivelycoupling the service data units to any one of the medium access controlheaders; and the second step of transforming the formed protocol dataunit into a transport block with a predetermined size.

Preferably, the protocol data unit may include a plurality of fill bits.

Further, preferably, each of the medium access control headers mayinclude a mobile identifier region for in-band identification; a mediumaccess control-service access point identifier region for multiplexing alogical channel for service data with a corresponding one of the mediumaccess control headers; a radio link control-user plane identifierregion for multiplexing a radio link control-user entity; a mediumaccess control-service data unit length region and a medium accesscontrol-service data unit extension region or a medium accesscontrol-service data unit number region for cooperating to send theservice data; and a frame format identifier region for transfer ofinformation to a higher layer and contention resolution.

Further, preferably, the frame format identifier region may include aninformation format for transferring the information to the higher layer;and a command format or a response format for the contention resolution.

In accordance with another aspect of the present invention, there isprovided a method for formatting a signal in a mobile communicationsystem by appending a plurality of medium access control headers to aplurality of medium access control-service data units for data transferbetween a mobile station and network in the mobile communication system,comprising the first step of, if the service data units have differentcharacteristics, forming a medium access control-protocol data unit bysequentially coupling each of the service data units and each of themedium access control headers; and the second step of transforming theformed protocol data unit into a transport block with a predeterminedsize.

Preferably, the first step may include the step of sequentially formingthe medium access control headers and then appending each of the servicedata units to a corresponding one of the medium access control headerssubsequently thereto.

In accordance with yet another aspect of the present invention, there isprovided a method for formatting a signal in a mobile communicationsystem by appending a plurality of medium access control headers to aplurality of medium access control-service data units for data transferbetween a mobile station and network in said mobile communicationsystem, comprising the first step of, if said service data units havethe same characteristics, forming a medium access control-protocol dataunit by successively coupling said service data units to any one of saidmedium access control headers; the second step of, if said service dataunits have different characteristics, forming said protocol data unit bysequentially coupling each of said service data units and each of saidmedium access control headers; and the third step of transforming theformed protocol data unit into a transport block with a predeterminedsize.

In a feature of the present invention, a medium access control sublayerformats medium access control-protocol data units according to transportchannel characteristics in peer-to-peer communication in such a mannerthat the protocol data units can have different formats with respect todifferent transport channels. This makes it possible to provide moreefficient functions.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 a is a view illustrating a data flow for a non-ARQ-type radioaccess bearer service to which a conventional method for formatting asignal in a mobile communication system is applied;

FIG. 1 b is a view illustrating a data flow for an ARQ-type radio accessbearer service to which the conventional signal formatting method isapplied;

FIG. 2 is a view illustrating a data flow based on a method forformatting a signal in a mobile communication system in accordance withthe preferred embodiment of the present invention; and

FIG. 3 is a view showing a header format based on the signal formattingmethod in accordance with the preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A method for formatting a signal in a mobile communication system inaccordance with the preferred embodiment of the present invention willhereinafter be described with reference to FIGS. 2 and 3.

FIG. 2 is a view illustrating a data flow based on the signal formattingmethod in accordance with the preferred embodiment of the presentinvention, and FIG. 3 is a view showing a header formal based on thesignal formatting method in accordance with the preferred embodiment ofthe present invention.

In peer-to-peer communication between a mobile station and a network ina mobile communication system, first, an upper layer, or a radioresource control (RRC) layer, of the mobile station transfers data to aMAC sublayer through logical channels, or a synchronization controlchannel (SCCH) (time division duplexer (TDD)), a broadcast controlchannel (BCCH), a paging control channel (PCCH) and a common controlchannel (CCCH), and service access points (SAPs), as shown in FIG. 2.

An RLC-C layer of the mobile station transfers service data from the RRClayer to the MAC sublayer through a logical channel, or a dedicatedcontrol channel (DCCH), and an SAP.

An RLC-U layer of the mobile station transfers service data from a linkaccess control (LAC) layer to the MAC sublayer through a logicalchannel, or a dedicated traffic channel (DTCH), and an SAP.

As stated previously with reference to FIGS. 1 a and 1 b, the RLC-U/Clayers receive service data composed of a plurality of PUs through theassociated logical channels and SAPs and append segmentation andreassembly headers respectively to the received service data to segmentit into parts of a size suitable to a sending rate and reassemble thesegmented parts. Then, the RLC-U/C layers transfer the resultant RLC-U/CPDUs to the MAC sublayer. The MAC sublayer appends multiplexing headersrespectively to the RLC-U/C PDUs from the RLC-U/C layers to multiplexthem to transport channels and produces the resultant MAC-PDUs.

The MAC-PDU is composed of a MAC header, a MAC-SDU and fill bits, whichare used to fit the size of a transport block. The MAC-PDU may have aplurality of MAC-SDUs in a non-ARQ-type service. The following tables 1,2a and 2b show MAC-PDU formats in the non-ARQ-type service. TABLE 1 MACheader MAC-SDU MAC-SDU MAC-SDU Fill bits

TABLE 2a MAC MAC MAC MAC-SDU MAC-SDU MAC-SDU header header header

TABLE 2b MAC MAC-SDU MAC MAC-SDU MAC MAC-SDU header header header

In an ARQ-type service, the MAC-PDU includes only one MAC-SDU and onlyone MAC header.

In the non-ARQ-type service, the transport block is variable in sizebecause the data rate is variable, too.

The PU has a size corresponding to that of the smallest transport block,and a plurality of MAC-SDUs and a plurality of MAC headers may bepresent in one MAC-PDU.

The above table 1 shows that one MAC-PDU contains only-one MAC header.Here, the MAC header may be either fixed or not in size, and allMAC-SDUs in the MAC-PDU are limited to have the same characteristics.

However, the presence of a plurality of MAC-SDUs in the above table 1makes it possible to minimize overhead radio,

The above tables 2a and 2b show that MAC headers are present for aplurality of MAC-SDUs in one MAC-PDU, respectively. Here, each of theMAC headers may be either fixed or not in size, and the MAC-SDUs in theMAC-PDU have different characteristics such as, for example, differentMAC-SAPs. TABLE 3 Functions Transport Channels (Services) FACH/ PDUfield associated BCH PCH RACH DSCH DCH MAC Mobile In-band identification• • header identifier MAC-SAPs Multiplexing logical • • • identifierchannels RLC-Us Multiplexing multiple • • • identifier RLC-Us Length ofData transfer • • • • • MAC-SDU Extension of Data transfer • • • • •MAC-SDU (Number of MAC-SDU) Frame format Contention resolution • • • • •identifier MAC-SDU Data transfer • • • • • Fill bits Fitting thetransport • • • • • block size

As stated above, the MAC-PDU is composed of a MAC header, a MAC-PDU andfill bits. As seen from the above table 3, the MAC header has differentcontents according to transport channels.

For example, in-band identification and MAC-SAP identifier functions ofthe MAC sublayer are not executed in transport channels, or a broadcastchannel (BCH) and a paging channel (PCH)

As shown in the above table 3, the MAC header is composed of a pluralityof regions, or mobile identifier, MAC-SAPs identifier, RLC-Usidentifier, frame format identifier, extension of MAC-SDU (number ofMAC-SDU) and length of MAC-SDU regions.

The mobile identifier region is used for in-band identification for aspecific mobile station when the specific mobile station is addressedthrough a common downlink channel or it uses a random access channel.The responsibility for user identification lies with the MAC sublayer.Mobile identification becomes a radio network temporary identity when aRRC connection is present and a random radio network temporary identitywhen no RRC connection is present.

The MAC-SAPs identifier region is used to demultiplex transport blockswhich the MAC sublayer receives from a layer 1 through transportchannels, to corresponding MAC-SAPs.

For example, transport blocks received through transport channels, or adownlink shared channel (DSCH) and a dedicated channel (DCH), may berouted to a DCCH-SAP or a DTCH-SAP.

The RLC-Us identifier region indicates that a plurality of RLC-Uentities are present for the DTCH-SAP and the MAC sublayer shoulddemultiplex transport blocks transferred from a physical layerrespectively to the RLC-U entities. An RLC-U identifier in the MAC-PODUindicates an RLC-U entity to which the MAC-PDU is to be routed.

The MAC-SDU length region indicates that the MAC-SDU is varied inlength. The length of the MAC-SDU must definitely be represented.

The MAC-SDU number region (MAC-SDU extension region) is used when theMAC-PDU includes a plurality of MAC-SDUs.

Namely, the MAC-SDU number region indicates that only one MAC header isused for a plurality of MAC-SDUs as shown in the table 1, and theMAC-SDU extension region indicates whether the subsequent MAC-SDU ispresent and that each MAC-SDU has an MAC header as shown in the tables2a and 2b. These regions are not required in a ARQ-type service where aplurality of MAC-SDUs are not present.

The frame format identifier region is composed of three formats, or aninformation format, a command format and a response format, as seen fromthe below table 4.

When the MAC sublayer receives an information format, it transfers aMAC-SDU directly to a higher layer entity.

The command format and response format are used for contentionresolution. TABLE 4 Format Type Function MAC-SDU from where InformationFormat Normal transmission RLC-U/C PDU from higher layer Command FormatCommand requiring the RLC-U/C PDU response for contention from higherlayer resolution Response Format Response for command RLC-U/C PDUreceived from peer MAC entity

If the MAC sublayer receives a command format contained in a MAC-SDUfrom a peer entity, then it has to transfer a response format with thesame value as that of the received command format to the peer entity.

The BCH, PCH, a forward access channel (FACH), a random access channel(RACH), the DSCH and DCH are transport channels. In the above table 3,“•” represents ones of the transport channels to which the regions ofthe MAC header are applicable.

FIG. 3 shows a PDU format of the RACH or FACH, which includes all of theregions of the MAC-PDU as mentioned above.

The RACH or FACH can be mapped to a logical channel, or the CCCH, DCCHor DTCH. The MAC-PDU must have an RLC-U identifier and a MAC-SAPidentifier. A contention resolution function can be executed through theRACH or FACH.

In this connection, the MAC-PDU includes a frame format identifier.Also, a mobile identifier is included in the MAC-PDU for in-band useridentification for the RACH or FACH.

As a result, the MAC sublayer formats a MAC header in the above manner,selects a transport channel according to regions of the resultant MACheader and transforms the MAC header and service data into a transportblock with a size receivable by a physical layer. Then, the MAC sublayersends the resultant transport block to the network through any one ofphysical channels, or a synchronization channel (SCH), a primary commoncontrol physical channel (CCPCH), a secondary CCPCH, a physical randomaccess channel (PRACH) and a dedicated physical data channel (DPDCH).

Upon receiving the transport block sent from the mobile station throughthe physical channel, the network performs the opposite procedure tothat of the mobile station to separate the received transport block intoone or more MAC headers and a plurality of MAC-SDUs and perform theassociated signal processing.

Further, for communication between the network and mobile station in themobile communication system, the network performs the same procedure asthat of the mobile station to format a signal according to a transportchannel and send the resultant transport block with a predetermined sizethrough a physical channel. Then, the mobile station receives thetransport block sent from the network and performs the oppositeprocedure to that of the network to separate the received transportblock into one or more MAC headers and a plurality of MAC-SDUs andperform the associated signal processing.

As apparent from the above description, according to the presentinvention, the MAC sublayer formats MAC-PDUs according to transportchannel characteristics in peer-to-peer communication in such a mannerthat the MAC-PDUs can have different formats with respect to differenttransport channels. Therefore, the present invention has the effect ofproviding more efficient functions.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

1-24. (canceled)
 25. A structure of a protocol data unit (PDU) generated in a medium access control (MAC) layer of a transmitting side in a communication system, comprising: at least two service data units (SDUs) transferred from an upper layer; and at least two headers providing control information for the at least two service data units (SDUs), respectively.
 26. The structure of claim 25, wherein the at least two headers are located ahead of the at least two service data units (SDUs).
 27. The structure of claim 26, wherein a sequence of the at least two headers is identical to a sequence of the at least two service data units (SDUs).
 28. The structure of claim 25, wherein each header is located right ahead of a corresponding service data unit (SDU).
 29. The structure of claim 28, wherein each header includes a MAC-SDU length region indicating a size of the corresponding service data unit (SDU).
 30. The structure of claim 25, wherein the header is a MAC header.
 31. The structure of claim 30, wherein each MAC header includes an identification region for identifying a corresponding service data unit (SDU).
 32. The structure of claim 30, wherein the at least two service data units (SDUs) include different kinds of data each other.
 33. The structure of claim 30, wherein each MAC header includes a region for identifying a logical channel through which the corresponding service data unit (SDU) is transferred.
 34. The structure of claim 33, wherein each MAC header further includes a region for identifying a size of the corresponding service data unit (SDU).
 35. A structure of a protocol data unit (PDU) generated in a medium access control (MAC) layer of a transmitting side in a communication system, comprising: at least two service data units (SDUs) transferred from an upper layer; and at least two headers providing control information for the at least two service data units (SDUs), wherein each header is located right ahead of a corresponding service data unit (SDU).
 36. The structure of claim 35, wherein each header includes an identification region for identifying the corresponding service data unit (SDU).
 37. The structure of claim 36, wherein each header further includes a length region for identifying a size of the corresponding service data unit (SDU).
 38. The structure of claim 35, further comprising ‘Fill bits’ region after at least one service data unit (SDU).
 39. A method of data processing in a medium access control (MAC) layer of a transmitting side in a communication system, comprising: receiving at least two service data units (SDUs) transferred from an upper layer; and transmitting a protocol data unit (PDU) including the at least two service data units (SDUs) to a lower layer, wherein the protocol data unit (PDU) includes at least two headers providing control information for the at least two service data units (SDUs), each header being located right ahead of a corresponding service data unit (SDU).
 40. The method of claim 39, wherein each header includes an identification region for identifying the corresponding service data unit (SDU).
 41. The method of claim 40, wherein each header further includes a length region for identifying a size of the corresponding service data unit (SDU).
 42. The method of claim 39, further comprising ‘Fill bits’ region after at least one service data unit (SDU). 